So, I’m trying to get the most out of my 60-day trial of ESRI’s Spatial Analyst. I finally downloaded a DEM file from GIS Data Depot. The file I ended up with was a 2.5 MB tarball (TAR.GZ)… I’ve never had to open one of those before in Windows (unlike during my Ubuntu adventures). So I installed 7-ZIP to unzip (I love small programs like that!). Then I had to convert the unzipped pile of DDF’s into a DEM using SDTS2DEM.exe. Finally, I could open the DEM in ArcMap, build pyramids, and display the surface. Then I contoured and compared the contour lines with those from the USGS DRG TIFF, and they were remarkably similar. Wow, DEM files are pretty neat. I hope that we can get a full license of Spatial Analyst soon.